Pressure regulating valves typically have an inflow port, a return flow port and an outlet port. By means of a control slide valve actuated by an electromagnet, the pressure at the outlet port is set to a value corresponding to the magnetic force. The corresponding armature is often, as in U.S. Pat. No. 5,571,248 or DE 10 2014 004 796 A1, for instance, surrounded by the pressure at the return flow port. The pressure around the armature is hence comparatively low. Air bubbles in the pressure fluid around the armature are hence not automatically conveyed out of the pressure regulating valve. Rather, a complex bleeding is necessary.
In addition, in pressure regulating valves the pressure at the work port typically produces at the control slide valve a force directed in the direction of the longitudinal axis. For this purpose, for instance from U.S. Pat. No. 5,571,248, a pressure transmission pin, which at one longitudinal end projects into the control slide valve, is known. The control slide valve is designed such that the pressure at the outlet port effectively acts only on an area of the control side valve which is equal to the cross-sectional area of the pressure transmission pin.
In the pressure regulating valve according to EP 1 209 327 A2, on the outer peripheral surface of the control slide valve is instead provided a leap in diameter, wherein effectively only the appropriate annular surface is pressurized by the pressure at the outlet port. The drawback of this solution consists in said annular surface being comparatively large. Should it be wished to reduce the size of this, then the leap in diameter would have to be chosen so small that it can no longer be produced in a process-reliable manner. By contrast, the abovementioned pressure transmission pin can have a very small cross-sectional area. In EP 1 209 327 A2, the armature is surrounded, furthermore, by the pressure at the work port, so that EP 1 209 327 A2 is regarded as the closest prior art.